The field of the disclosure relates generally to foreign object debris (FOD) detection, and more specifically, to methods and systems for enhancing backscatter x-ray FOD detection.
As is known, aircraft and other complex structures are fabricated and subsequently modified in manners that sometimes require substantial disassembly and re-assembly of portions thereof. During fabrication, for example, it is common to place components together for a drilling operation and then separate such components for deburring operations prior to a final assembly of such components. Such operations result in FOD from the metal or composite shavings that result from the drilling and deburring operations. The tools and bits tools used to accomplish such operations, if left in a position and forgotten, may also end up as FOD. Likewise, the drilling plates used to properly align the drilling tools and bits can end up as FOD if not properly disposed of. In fact, FOD could be any type of objects unintentionally left in a fabricated structure.
In the aircraft example, modifications may involve the removal of exterior and/or interior panels to facilitate access to components of the aircraft that are contained within compartments located behind the panels. When such panels are removed, foreign objects are often introduced into the compartments. Items such as tools, fasteners, manufacturing material, personal objects, and other debris may be inadvertently left behind in such compartments after the modifications are complete. Such items constitute FOD.
Thus, is it easy to understand that during fabrication and modification of aircraft, as well as other complex assemblies such as land vehicles, water vehicles, electrical boxes and other complex machinery, there are opportunities to unintentionally leave items and other debris behind in the areas where work was performed.
As is easily understood, the presence of FOD in an aircraft or other complex machine is undesirable as the FOD may interfere with proper operation of such machines. However, once the fabrication and/or modifications have been completed to such machines, it is difficult to determine whether or not there is FOD present. One contemporary practice is to have technicians visually inspect work areas. However, such visual inspection is too often insufficient as FOD may be overlooked because of accessibility and inefficiency of manual inspection tools.
In addition, processes are known in which images taken using backscatter X-ray imaging technology are subtracted from one another, but these processes do not enhance the detection of hidden FOD. Specifically, existing X-ray processes image everything within the structure and are difficult to interpret because the multiple layers and hardware associated with such structures can mask FOD that may be hidden and not clearly visible in the image.